The invention discloses a puncture navigation method for CT guided liver tumor radiofrequency ablation. The method comprises the steps that markers which can be identified by CT are placed on the bodysurface of a patient suffered from liver tumor, and three-dimensional structures of the liver tumor, liver and key dissection structures (great vessels, lung, heart, stomach, kidney, gallbladder, skin and skeleton) are automatically and rapidly extracted from CT sequence scanning images in the CT guided liver tumor radiofrequency ablation; real-time automatic planning of puncture routes is conducted to obtain the optimal puncture route; spatial matching is conducted on a patient coordinate system P, a CT image coordinate system I and an electromagnetic positioning instrument coordinate systemE; information of the starting point, ending point, length, angle and the like of the optimal puncture route is displayed in CT image space; the moving of needle tip of an ablation needle is executedto reach the starting point of the optimal puncture route to conduct real-time navigation; after the needle tip of the ablation needle is moved to the starting point of the optimal puncture route, real-time navigation of the puncturing of the ablation needle is executed.